I had a big scare a few days ago when I ended up deleting my entire itunes library and then could not restore it from Time Machine due to some crazy permission error.

Apple does some funky stuff at the kernel level to make the time machine backups appear like real files (rather than the database that it is) in the Finder. So, you cannot use the finder to copy files over. However, you can use a fairly simple terminal command to save your music. I have since shared this with someone who used this to recover their iphoto library as well so this clearly works for more than just music.

You can use the command below by replacing everything after backupdb/ with the location of your time machine backup and then replacing the text in quotes with the folder where you want to copy stuff.